Raspberry Wicking Bed Project

I’ve been looking at wicking bed ideas for a while now and the more I see, the more I wish my existing beds were set up this way. For the past few years I have had my collection in raspberries in pots, but last year they didn’t enjoy the Summer and the crop was disappointing. Positioned along the back fence, they had to deal with too much afternoon summer sun, reliance on me watering them at least once a day in the heat, and although I attempted to net them, some of the harvest was also taken by a resident rat. The best position for them was in part shade, where they had been previously, though they needed to still be contained (as they quickly spread if in the ground). They were the perfect candidate for a wicking bed.

Wicking beds have the advantage of being water efficient with water being accessed from the reservoir below. Uneven watering can lead to plants bolting to seed or reduce crops, this system provides the plants with a readily available water source and helps to minimise this problem.

With a little forward planning, you can find some of your materials 2nd hand or free to help keep the costs down. Here are the basics –

Materials

Garden bed frame – I used the metal garden bed (these ones are from Greenlife Garden Products) but you can use anything – old fruit crates or an existing garden bed.

I positioned two beds in the partly shady area either side of one of our plum trees. In Summer I will net both beds and the tree together as one unit.

The garden beds needed to be level, and these larger metal beds have reinforcing bars between the two longer sides. While in a normal installation these would ideally be staggered at different levels, I had to position two at the base and two at the top for this project to allow for the plastic liner.

I covered the screws with pieces of yoga mat to protect the plastic from piercing and clamped the plastic to the frame to keep it in position.

I installed two stakes, one at either end of the bed, between the frame and the plastic as this will be used to help trellis the raspberry bushes. Yoga mats and cardboard boxes were placed on top of the plastic to protect it from the scoria.

Next, the PVC pipe, T-junction and agi pipe were all assembled and placed in the bottom of the bed, temporarily held in place with bricks and stones until the scoria was poured in.

The scoria was added to a depth of around 15cm.

On top of the scoria I placed pieces of shade cloth, and installed the overflow pipe (a narrow PVC pipe) where the soil meets the stones to ensure the soil does not get too wet and excess water can readily drain away.

Good quality soil, compost and potting mix (around 20cm deep) was added along with the raspberry plants and then finally, a covering of sugar cane mulch.

If planted earlier in the season I would have put together a more sturdy climbing frame, but the plants have well and truly taken off and the best I could do was to pull across some fabric string an support them until they die back in Winter.

The clamps will need to be removed and the plastic cut to the same height as the top edge of the garden bed, but they’re essentially done and I’m really happy with the way they came together.

I’m looking forward to seeing how the beds perform over the warmer months. Here’s hoping for a great crop of raspberries this year!

Comments

I used pond liner rather than builder’s plastic to line my wicking bed. It’s meant for fish, so is far less likely to leach toxic material into the water. It’s far more expensive, but is also much stronger so should last longer.
While I expect your bed to meet most of your objectives, I wonder if the raspberry root system can cope with such a small depth. 30 cms is the maximum suggested for wicking beds. Please keep us updated.
In the meantime I’ll continue with covering my raspberries on extra hot days.

Hi Tash, love to see how these end up in the wicking system bed. I have 2 wicking pots (GardenSmart and the Vegepod) of different sizes and while I love how they work, I have also come across many wicking systems beds in community gardens where the soil was dank and sour, staying very wet over winter. I’m sure they would work better in summer but would love to see what your results are like.
Cheers!